Labial consonants are consonants in which one or both lips are the active articulator. The two common labial articulations are bilabials, articulated using both lips, and labiodentals, articulated with the lower lip against the upper teeth, both of which are present in English. A third labial articulation is dentolabials, articulated with the upper lip against the lower teeth (the reverse of labiodental), normally only found in pathological speech. Generally precluded are linguolabials, in which the tip of the tongue contacts the posterior side of the upper lip, making them coronals, though sometimes, they behave as labial consonants.[clarification needed]

Very few languages, however, make a distinction purely between bilabials and labiodentals, making "labial" usually a sufficient specification of a language's phonemes. One exception is Ewe, which has both kinds of fricatives, but the labiodentals are produced with greater articulatory force.

Many of these languages are transcribed with /w/ and with labialized consonants. However, it is not always clear to what extent the lips are involved in such sounds. In the Iroquoian languages, for example, /w/ involved little apparent rounding of the lips. See the Tillamook language for an example of a language with "rounded" consonants and vowels that do not have any actual labialization.